Does Slaine's death really have to be resolved? Why can't It just finish, whereever and whenever that is. And then just, reboot it! Take it back to it's original feel. Lose the celto-hippy fantasy themes. Take it back to 12,000BC. Properly prehistoric!
Imagine the beginning of the"new" Slaine. Riding on the back of a giant Auroch, a pair of twin stone axes by his side. Wrapped in the fur of a great cave bear, which he personally had killed, to keep him warm in this harsh proto-european wilderness. Staring across the new wildernesses left from the retreat of the last ice age. Wodering where his travels will take him and who, or what, he will meet in this new world. The modern age of man has just begun. The bow, farmimg, fisheries, domestication of dogs, and other animals, the rise of pottery and technologies of all sorts. The real age of the gods. Not the namy-pamby imagery we are all used to seeing, but the real heroes of the human race. This was the time when man first really began to tame the savage world. By all means have wooly mammoths, sabre-tooth lions, neanderthals etc. Perhaps the last degenerant remnants of the age of dinosaurs!
Think of it as a hardcore version of Wolf-brother by Michelle Paver, with the screenplay by John Milius (the guy who did the first Conan movie) or Peter Jackson! But with all the H.G.Wells-ian fantasy elements we all like.
It's just a thought, but I'd like to read that. Heck! I'd love to draw that!